TY - CHAP

T1 - IR Spectroscopy of Photoprocesses in Heterogeneous Systems

AU - Tsyganenko, A.

PY - 2018

Y1 - 2018

N2 - A review is presented on the photostimulated processes in heterogeneous systems studied by vibrational spectroscopy. Started in the early 40th in the works by acad. Terenin, the method was used to detect the products or the intermediates of photooxidation on solid photocatalysts. If the molecules are too stable and resist both photooxidation and ozonolysis, simultaneous action of ozone and UV irradiation reveals a synergetic effect, leading to their degradation. UV irradiation of supported V or Mo in reducing gases leads to selective creation of active cationic sites in certain oxidation state. After appearance of tunable pulse lasers for IR region studies of relaxation processes at the surfaces became available. By means of pump-probe method the characteristic times of energy relaxation were measured. Tunable lasers were also used for selective excitation of the vibrational modes of certain isotopomers in adsorbed isotopic mixtures in order to achieve isotope separation. The experiments, however, show that the selective desorption does not occur because of a quick energy transfer between the adsorbed species due to strong dipole coupling, which can be studied by means of isotopic dilution method. Some molecules exhibit linkage isomerism when the same molecule can be bound to the same cationic sites in different ways. So, CO in zeolites forms with the cations C- and O-bonded species. The two states have different energies, the less energetically favorable species can be considered as an excited state, whose energy could be used for activation of some reactions. Experiments on photoinduced isomerization are in progress. The work was supported by the Russian Foundation for Basic Research, Grant 17-03-01372

AB - A review is presented on the photostimulated processes in heterogeneous systems studied by vibrational spectroscopy. Started in the early 40th in the works by acad. Terenin, the method was used to detect the products or the intermediates of photooxidation on solid photocatalysts. If the molecules are too stable and resist both photooxidation and ozonolysis, simultaneous action of ozone and UV irradiation reveals a synergetic effect, leading to their degradation. UV irradiation of supported V or Mo in reducing gases leads to selective creation of active cationic sites in certain oxidation state. After appearance of tunable pulse lasers for IR region studies of relaxation processes at the surfaces became available. By means of pump-probe method the characteristic times of energy relaxation were measured. Tunable lasers were also used for selective excitation of the vibrational modes of certain isotopomers in adsorbed isotopic mixtures in order to achieve isotope separation. The experiments, however, show that the selective desorption does not occur because of a quick energy transfer between the adsorbed species due to strong dipole coupling, which can be studied by means of isotopic dilution method. Some molecules exhibit linkage isomerism when the same molecule can be bound to the same cationic sites in different ways. So, CO in zeolites forms with the cations C- and O-bonded species. The two states have different energies, the less energetically favorable species can be considered as an excited state, whose energy could be used for activation of some reactions. Experiments on photoinduced isomerization are in progress. The work was supported by the Russian Foundation for Basic Research, Grant 17-03-01372

UR - https://www.interphotonics.org/images/files/book_of_abstracts_interphotonics_2018.pdf

M3 - Conference abstracts

SP - 70

BT - International Conference on Photonics Research (INTERPHOTONICS 2018)

Y2 - 9 October 2018 through 12 October 2018

ER -